Pulley-block.



W. N. HEAD.

PULLEY BLOCK,

APPLIOATION' IILED MAY 15, 1907.

905,309. Patented Dec.,1, 1903.

UNITED sTArns PATENT OFFICE.

WILLIAM renew, on NEW YORK, N. Y, ASSIGNOR 'ro enonen AGOBIAN, or

BROOKLYN,

NEW YORK.

PULLEY-BLOGK.

Application filed May 15,

tan, in the county of New York and State of New York, have inventedcertain new and useful Improvements in Pulley-Blocks, of which thefollowing is a specification.

The object of this invention is to provide a new and improved pulleyblock which is simple in construction, strong, durable and reliable andis provided with a means for automatically locking the rope whenever thesame is released or breaks, which means is automatically thrown out ofaction as long as the load is being raised or lifted and which meanspermits of lowering the load at any desired speed or checking itsdescent at will.

In the accompanying drawings, in which like letters of referenceindicate like parts in all the figures: Figure 1 is a side view of myimproved pulley block. Fig. 2 is an edge view of the same. Fig. 3 is anenlarged longitudinal sectional view showing the locking means.

The pulley block is constructed with a casing composed of two sideplates A, a central partition B between and parallel with the sideplates and top, bottom and intermediate cross bolts C, D and Erespectively, 011 which latter the sheaves F are mounted between theside plates A and the partition B. A suspension hook G is swiveled inthe top of the casing and an eye H for securing the fixed end of thesuspension or hoisting cable is formed at the bottom of one side plate.Above the sheaves F a cross bolt or pin J is secured in the casing andon the same the two locking levers K are mounted, one in eachcompartment formed by a side plate A and the partition 13. The lockinglevers K are alike and each has a long shank or arm L and a shortershank M united by a cross piece N. A short link 0 is pivoted between theends of the longer shanks 'or arms L of the two levers K thus unitingthe two levers at their outer ends and a check rope is to be fastened tosaid link or its substitute. At the inner end of each lever K a shoe Pis formed which has a curved groove Q, eccentric to the pin J andextending to the free end of the shoe and provided with inclined curvedrifiles corresponding to the twists of the rope. Each shoe also has asmooth grooved part R Specification of Letters Patent.

1907; Serial No. 373,760.

Patented Dec. 1, 1908.

l which when the lever K. is in the position shown in Fig. 3 issubstantially concentric with the sheave and does not interfere with themovement of the rope. A short helical spring S is attached to the crosspiece N and to a cross bolt or pin J in the casing and these springsnormally hold the locking levers K in the position shown in Fig. 1.

The pull on the hoisting rope when lifting the load is in the directionof the arrow Fig. 1 and the rope easily passes under the shoes, whichgive under the strain. As soon as the hoisting rope is slackened orreleased the load pulls it in the inverse direction of the arrow on bothsheaves and the rope is instantly jammed between the sheave and theriffled groove part Q of the shoe and thus checked and locked instantlyand automatically on both sheaves. If the load is to be lowered thelevers K are brought into the position shown in Fig. 3 by pulling on therope connected with the link 0 whereby the springs S are brought ingreater tension and as soon as the rope connected with said 'levers isreleased the springs S instantly throw the levers K into the positionshown in Fig. 1 and then look the hoisting rope. \Vhen the levers K arein the position shown in Fig. 3 the hoisting rope passes through thesmooth grooved part B which does not interfere with the free movement ofthe hoisting rope in either direction. When the load descends toorapidly but is not to be checked entirely but only its speed of descentreduced the outer ends of the levers K are pulled down a trifle more sothat the smooth grooved part B acts as a friction brake shoe, thusretarding the speed of movement of the hoisting rope under the action ofthe descending load. As the brake shoes act on the rope on both sheaves,but a slight pull on the check rope is suflicient to retard the speed ofdescent.

Having described my invention what I claim as new and desire to secureby Letters Patent is 1. In a pulley block, the combination with acasing, of a sheave mounted therein, a brake lever pivoted above thesheave and provided with a shoe at one end, said shoe being providedwith a curved cam groove provided with riftles, and with a smooth curvedgroove at the inner end of the curved rifiled groove and extendinglengthwise of the lever, and a spring connected to the easing and to thelever for normally pressing the riflled groove upon the rope on thebrake levers being united, substantially as sheave, substantially as setforth. set forth.

2. In a pulley block, the combination with Signed at New York city inthe county of a casing, of two sheaves side by side, a brake New Yorkand State of New York this 14th 5'lever pivoted above each sheave eachbrake day of May A. D. 1907.

lever having a shoe provided with a curved A I y I riffied grooveextending to the end of the VILLTAM shoe and with a small grooved smoothpart Witnesses:

at the inner end of the rifiled part extending DAVID C. THYTE,

10 lengthwise of the lever the outerends of said l OSCAR F. G'UNZ.

